It depends on what typ you have. There are 3 subspecies to it . Echinacea Augustifolia rt. is the most exspensive. The next is Echinacea Pallidia and last is Echinacea purpurea .
Let me know what you have in your area. If you don't know the typ, look each one of the typs I have listed up on the internet and they will show pictures of thge plants.
To give you a clue on which ones you have. Augustifolia or the Pallidia. Both of these coneflowers have the leaves growing up from the bottom of the stem. The leaves are oblong or lance shaped. Leaves and stem are thick and covered with bristly hairs. The roots of these two species have thick, long, taproots that twist lengthwise. Dried root is grayish brown on the outside and wrinkled lengthwise. The roots have a distinct, sweetish oder.
The purpurea roots are more fibrous and there is no main tap root. roots range from2 to 3 inches long. The main root is knobby on top where the stem is and has many smaller roots growing off of it. The leaves are lance shaped but only 2-6 inches long usually and grow all the way up the stem of the plants. They are hairy and unevenly toothed.